A production paint application process where paint is applied to a substrate, such as, for example a vehicle body moving through a paint booth, requires paint to be transferred from a paint reservoir to a paint applicator robot disposed in the paint booth, where paint is applied by a rotary atomizer as an integral part of the paint applicator robot. Typically, the rotary atomizer includes a turbine device disposed in a housing, a rotating bell unit having a shaft connected to a bell cup and disposed in and rotatable relative to the turbine device and the housing. The bell cup has a generally conical overflow surface between a radially inward central axial opening and a radially outward atomizing edge. At or near the radially outward atomizing edge, the angle of the overflow surface relative to the axis of the bell cup decreases sharply to form a lip adjacent the atomizing edge. The purpose of this lip is to generally direct the atomized paint more axially forward and reduce radial scatter. Typically, an air shaping ring is attached to the turbine device to improve distribution of the paint onto the vehicle body being painted.
The art is replete with prior art designs of an air shaping rings for a rotary atomizer. The U.S. Pat. No. 5,775,598 to Takayama et al.; U.S. Pat. No. 5,727,735 to Baumann et al.; U.S. Pat. No. 6,189,804 and U.S. Pat. No. 6,623,561 both to Vetter et al.; and the United States Patent Publication Nos. 2005/0001077 and 2003/0010840 both to Kon et al. The United States Patent Publication No. 2005/0001077 to Kon et al., for example, teaches a rotary atomizer having a housing, a turbine device disposed in the housing, a bell unit disposed in and rotatable relative the turbine device. An air shaping ring is disposed about the turbine device and is connected to the housing by a partially threaded fastener extending to a hook to interconnect the air shaping ring with the housing. This design is complex and requires additional component, such as the aforementioned fastener to interconnect the housing with the air shaping ring.
The U.S. Pat. No. 6,623,561 to Vetter et al., on the other hand, teaches a rotary atomizer having a housing, a turbine device disposed in the housing, a bell unit disposed in and rotatable relative the turbine device. An air shaping ring is disposed about the turbine device and between the turbine device and the housing. The air shaping ring of the U.S. Pat. No. 6,623,561 to Vetter et al. does not require additional components, such as, for example, partially threaded fastener extending to a hook, taught by the United States Patent Publication No. 2005/0001077 to Kon et al. to interconnect the air shaping ring with the housing. Hence, the air shaping ring and the turbine device taught by the U.S. Pat. No. 6,623,561 to Vetter et al. do not provide for constant surface to surface contact between the air shaping ring and the turbine device. In addition, none of the prior art patents teaches an improved design of the atomizer having improved rigidly stabilized connection between the turbine device and the housing for maintaining a fixed air gap between the shaft and a paint pipe or line extending through the shaft for keeping the shaft at a fixed distance relative to the paint line as the shaft rotates around the axis.
The goal of the invention is therefore to provide an improved design of the turbine device to eliminate at least one of the aforementioned problems associated with prior art atomizers.